The invention relates to block transmission systems. More specifically, the invention relates to a method and system for performing channel estimation in a multiple antenna block transmission system.
In some known block transmission systems, for example, it is desirable to transmit a preamble from a first transmit antenna for synchronizing and training receivers or subscriber units that are capable of decoding signals from a single transmit antenna. However there may be other subscriber units that can decode signals from multiple transmit antennas. In order to train these remaining transmit antennas to the same extent as the first transmit antenna, considerable overhead is incurred. These remaining transmit antennas may transmit with lower pilot density to avoid these overheads. This, in turn may limit the delay spread of the channels that can be estimated or effect the channel estimation quality for these remaining transmit antennas.
In some block transmission systems, the quality of the pilots of a first transmit antenna may be different from the quality of the pilots of remaining transmit antennas, due to different boosting, different interference (as seen at the receiver) or other factors. This in turn effects the quality of the channel estimation corresponding to the first transmit antenna.
Therefore there is need for a method and system that improves the channel estimation quality and increases the delay spread of the channels that can be estimated in such block transmission systems.